Hero TV considers her to be the Idol Superstar of the hero world. Her costume includes crystal nails and freezing liquid guns. It also includes advertising for Pepsi NEX, a zero calorie Pepsi available in Japan developed by Suntory.

Early in the show, Karina becomes unsure of her direction as a hero, claiming she had only become one as a stepping stone to her ambition for a singing career. Kotetsu speaks with her following one of her piano performances, urging her to do what makes her happiest.

Even though Kotetsu is a goof and does some pretty stupid things, she eventually develops feelings towards him. Even the sudden knowledge that he has a young daughter drove her into a state of shock. The sudden revelation of him not dying during the H-01 attack made her burst into tears and hug him. In the epilogue, it is shown that her love for him is serious enough to make her read a book about how to make a single father (Kotetsu) fall in love.